The present invention generally relates to the treatment of reactive wastes, and more specifically relates to systems and methods for the disposal of reactive waste materials, particularly those wastes listed by the United States Environmental Protection Agency under EPA waste code D003, for example military and industrial explosives, propellants and munition items that require special disposal. The present systems and methods utilize much of the approach and logic described in U.S. Pat. No. 5,741,465, to the same inventor, however the present systems and methods provide improvements thereto.
The regulation of the disposal of hazardous waste is now a well established law. A subset of hazardous waste, that being the explosive waste materials is also very strictly regulated. In the past such materials were disposed of by open burning and open detonation and by high temperature incineration. Open disposal has been banned in most places and high temperature incineration has proven to be far too expensive. While numerous incineration devices exist which can destroy these reactive materials, the cost of using these devices has eliminated them from competing in the open market place due to cost of reaching the 2200 degree F heating requirements imposed by the United States Environmental Protection Agency (US EPA) for these incinerators. Devices of this type are set forth in U.S. Pat. No. 5,207,176. The present invention provides a manner to deactivate explosive materials that is economical, protective of the environment, and which complies with the standards of the US EPA.
The present invention qualifies as Best Demonstrated Available Technology (BDAT) for the treatment of category D003 reactive waste as defined by the US EPA. To meet this US EPA standard, the facility is designed to meet the US EPA regulations codified at 40 CFR 264.600 for xe2x80x9cMiscellaneous Unitsxe2x80x9d. The facility does not meet the standards of an incinerator as defined by US EPA in 40 CFR 264.340 xe2x80x9cIncineratorsxe2x80x9d.
Reactive wastes for which disposal is regulated by the US EPA are given the Hazardous Waste Code D003. Among the reactive wastes which must be treated in a controlled facility are detonators, gas generants, ammunition, pyrotechnics, propellants, emulsions, oxidizers, boosters, squibs, dynamite, explosive bolts, igniters, blasting caps, signals, smokes, flares, pharmaceuticals, grenades, mines, gunpowder, detonation cord, incendiary devices, explosive sludges, among others.
The present invention provides an improvement in design for the inexpensive disposal of these reactive wastes. For example, the facility in accordance with the present invention, can handle substantially larger detonations without damage thereto, in comparison to conventional incinerators. The facility in accordance with the present invention includes detonation bays which are highly armored are able to withstand high force detonations. Detonation devices within the detonation bays are designed to deflagrate propellants without the large expenditure of energy required by incinerators. The device heats items that pop only to the temperature required to initiate the reactions and takes advantage of the energetic material within the waste to complete the reaction. These and other features of the present invention provide substantial improvements over incinerators.
Further it should be appreciated that the processes for deactivating burnable or exploding reactive materials are significant because explosives are generally known of being capable of undergoing the quick chemical reaction of decomposition without the intervention of further reactants, especially without atmospheric oxygen. Because oxygen is not required for the decomposition of explosives, the process for deactivation is referred to as xe2x80x9cdeflagrationxe2x80x9d as opposed to combustion which, as is well known, takes place only with the addition of oxygen. A further explanation of deflagration of explosives is set forth in U.S. Pat. No. 5,423,271, which is incorporated herein by this specific reference thereto, to further distinguish the apparatus necessary for the deactivation of burnable and explosive materials.
The present design economically treats reactive wastes which burn or deflagrate, items which melt or pop, and items which undergo significant detonation without utilizing incineration temperatures and it does so economically and in compliance the regulations of the U.S. Environmental Protection Agency. None of the conventional, presently available systems and methods can accomplish this claim.
A reactive waste deactivation unit, or facility, in accordance with the present invention, is capable of continuously processing a wide spectrum of reactive wastes. This includes the previously enumerated list of reactive wastes and others falling into the three types of reactive waste described herein. Particularly, the facility contains a plurality of deactivation bays, each including a specific deactivation device providing means for initiating and sustaining a deactivation reaction in the deactivation bay. The plurality of deactivation bays are enclosed within a common outer expansion chamber. The expansion chamber stops shrapnel, controls and collects the emissions from each of the bays, collects the ash and residuals, minimizes noise, and routes all of the off gas, i.e. waste gases generated by the deactivation process, to an air pollution control system of an appropriate type to comply with federal, state, and local air emission regulations.
More particularly, the deactivation devices include different types of deactivation devices, each type of deactivation device being configured for deactivating a different class of reactive waste. Further, the facility may contain a plurality of each type of device.
Specifically, in one embodiment of the invention, the facility includes three different types of deactivation devices. More specifically, the three different types of deactivation devices include an electrical spark device for deflagrating burnable wastes, a direct contact heating device for melting and popping manufactured items, and a shielded, radiant heating device for deactivating munition items such as grenades and mines that undergo high order detonations. Any shrapnel produced by these reactions will be contained in the internal reaction bays while the heat, pressure, gas, and noise will be contained by the external expansion chamber.
The internal deactivation bays are designed of cylindrical steel barrels of sufficient strength to accommodate the reaction of the treated material. The external expansion chamber is designed to withstand the heat and pressure from all of the deactivation reactions and detonations produced from the reactions.
In accordance with a method of the present invention for substantially continuous deactivation of reactive waste, the waste is fed into each deactivation bay sequentially, and in a planned manner, by means of a feed chute mechanism extending between the deactivation bays and an outside operating platform. More particularly, each deactivation bay is provided with an individual feed chute having an accessible inlet adjacent the operating platform. A xe2x80x9cfeed chargexe2x80x9d of reactive waste is placed in one or more of the feed chute inlets and then is fed into the deactivation bays, preferably in a sequential, planned manner, by remote operation of pneumatic-actuated rotary valves disposed on each feed chute. The feed chutes may be comprised of structural steel tube in tubular or rectangular shape.
Preferably, waste feed rates are carefully controlled to allow completion of treatment of each feed charge prior to the introduction of an additional feed charge into a given bay. For example, a first feed charge is introduced into one of the plurality of deactivation bays and after an appropriate time period is allowed to pass, a second feed charge is fed into the another one of the bays. In a specific embodiment of the present invention, four deactivation bays are provided. A typical cycle time required to sequentially charge all four of the bays would average about one minute. The charging cycle is then repeated as the time required to complete deactivation treatment in each bay averages about one minute as well. For safety reasons, the operator platform is positioned outside and above the expansion chamber. In addition, a blast wall may be provided for further separating the operators from reactions taking place in the unit.
In a specific embodiment of a method, in accordance with the present invention, for the continuous deactivation of reactive wastes, the method includes the step of separating the incoming wastes into three classes the first class being propellants and explosive powders burnable in an unconfined state without detonation thereof, a second class being manufactured devices capable of being melted or popped without a detonation, and a third class of munition items capable of being detonated in an armored bay.
In addition, the method may further comprise the steps of performing an analysis on the materials and the manufactured items, in accordance with a waste analysis plan, and determining an appropriate waste feed rate. The appropriate waste feed rate is a feed rate that the facility can safely process and that which will not exceed applicable air pollution standards.
Next, the method comprises the step of loading the determined allowable waste feed of each class into the deactivation bays, with each bay being suitable for deactivation of one of the three classes of reactive waste hereinabove set forth.
A computerized control system may be used to regulate the waste feeds, the heating of the bays, the system air flow, temperatures in the expansion chamber, the operation of an appropriate air pollution control system, and the cooling air to assure the system operates within safety standards and that it complies with the applicable air pollution control standards. The entire facility is designed and operated in a manner completely different from an xe2x80x9cincineratorxe2x80x9d as defined by the U.S. Environmental Protection Agency.
Importantly, the unit or facility in accordance with the present invention includes a residual waste removal system. Specifically, the waste removal system comprises a mechanism for removing ash, shrapnel and/or other materials accumulated in the deactivation bays. More specifically, each deactivation bay may include a releasable bay floor. For example, each treatment bay is equipped with an automatically operable, rotatable bay floor and release mechanism. Advantageously, this feature allows all residual material from the deactivation reactions to be dropped or xe2x80x9cdumpedxe2x80x9d from the bottom of the bay, and into a lower portion of the expansion chamber. The lower portion of the expansion chamber may include structure, such as sloped surfaces, which define a common outlet through which all of the residuals will fall. In addition, the expansion chamber is preferably adapted to accommodate a movable container element, for example a wheeled cart, bin or hopper, to be passed under the outlet so that the ash, melted debris, shrapnel and other non-reactive residuals may fall by gravity into the container element for removal and disposal in a suitable manner.
The air pollution control system feature of the present invention may comprise a gas cooling system, a cyclone separator, a filtration unit and a venting stack. The cooling system may for example comprise a length of coiled or twisted ducting disposed between an outlet of the expansion chamber and a cyclone inlet. Preferably, the ducting has a length and structure which is conducive to providing initial cooling of hot waste gasses emitted from the expansion chamber before the gasses enter the cyclone. The cyclone serves to remove particulate matter from the cooled waste gasses and as a mixer to ensure a homogenous temperature of the gasses as the gasses enter the filtration unit. The filtration unit may comprise a bag house designed to thoroughly clean and filter the waste gasses prior to venting the gasses through the stack. A draft fan connected between the bag house and the stack provides for further cooling by inducing ambient air into cleaned waste gasses.